Question: Simplify $\left( \frac{1}{2k} \right)^{-2} \cdot (-k)^3$.
Solution: $\left( \frac{1}{2k} \right)^{-2} \cdot (-k)^3 = (2k)^2 \cdot (-k)^3 = 4k^2 \cdot (-k^3) = \boxed{-4k^5}$.